In a magnetic rigid disk storage device, a rotating disk is employed to store information in small magnetized domains strategically located on the disk surface. A large quantity of information can be manipulated in a small physical volume by providing timely and accurate access to these domains for the purposes of recording and retrieving information.
Typical construction of rigid disk storage device consists of a frame to provide attachment points and orientation for other components, a spindle capable of producing stable rotation of the rigid disk(s) upon which the information will be stored, a read/write transducer head capable of flying in close proximity to the rigid disk(s), thus enabling the creation of magnetic domains on the rigid disk, a suspension for orienting the transducer head and providing forces and compliances necessary for proper transducer operation, and an actuator for positioning the suspension and thus the read/write transducer head or slider. Continued development of transducers/sliders has created the need for an improved combined gimbal and suspension design that will provide the necessary stiffnesses to allow the head to fly over the disks at the proper attitude for maximum read/write performance.
Conventionally available magnetic head gimbal designs for rigid disk drives allow magnetic read/write heads to pitch about a first axis and roll about a second axis orthogonal to the first axis when imperfections in the disk drive assembly tend to place the heads in improper positions relative to the surface of the disk. The present invention is designed to allow significant reductions in the pitch and roll axis stiffness of the head gimbal assembly, thus allowing the head to more readily maintain proper attitude. At the same time, the present invention is designed to increase the stiffness in the direction of the axis of actuation when compared to prior art designs which may have equivalently low pitch and roll stiffness.
Prior art gimbals of the type exhibited in U.S. Pat. Nos. 4,167,765 and 4,620,251, were all designed to provide acceptable pitch, roll, and lateral stiffness performance for a relatively crude level of slider performance which is rarely used in today's modern disk drive designs. Furthermore, said designs are not limited to but are most effective when the direction of actuation is coincident with the longitudinal axis of the gimbal and load beam. One solution to this problem can be seen in U.S. Pat. No. 4,868,694. Also, most current drive designs are not of this "linear" type but rather are classified as "rotary" due to actuation occurring orthogonal to the gimbal longitudinal axis. This motion is usually achieved by rotating the actuator and head gimbal assemblies about a common axis. This mode of actuation offers performance advantages in terms of data access time and economy of manufacture. Unfortunately, such prior art gimbals, especially when modified to lower their pitch and roll stiffness, also have reduced stiffness in the lateral direction and greater susceptibility to damage from shock loading.
Attempts at modifying prior art gimbals to function properly with newer slider designs have met with varying levels of success. Pitch and roll stiffness can be lowered by employing both thinner material and geometry changes but the reduction in lateral stiffness causes performance problems as indicated above.